Valve operating mechanism

ABSTRACT

Valve operating mechanism in which a rotatably mounted valve operating member is directly connected to the valve stem and is urged by a helical coil spring in one direction, characterized by a fluid pressure operated piston in a cylinder for moving the valve operating member in the opposite direction to compress and cock the spring and means including a latching member for holding the valve operating member against movement by the cocked spring and a solenoid for moving the latching member to an inoperative position thus to release the valve operating member to the action of said spring.

D United States Patent r 13,552,713

[72] lnventor Gunther K. E. Kleeberg [56] References Cited Lex'ngmi Mass- UNITED STATES PATENTS [211 3 085 781 4/1963 L P 25l/69X [22] Filed Apt 4 969 a ointe 3,153,317 10/1964 Manor et al. 251/31X [45] Patented Jan.5, 1971 327 74 9 6 Id 1 251 71X [73] Assignee EB. VSwtemslnc. 9, 4 1 /l 6 1e sen eta Warwick, R.l. Primary Examiner-Henry T. Klinksiek a corporation of Maryland Attorneys-Everett D. Littlefield and Merwin F. Ashley ABSTRACT: Valve operating mechanism in which a rotatably mounted valve operating member is directly connected to the valve stem and is urged by a helical coil 5 rin in one [54] VALVE OPERATlNGFMECHANISM direction, characterized by a fluid pressure oper ted piston in n Clams 6 Drawmg a cylinder for moving the valve operating member in the op- [52] U.S. Cl 251/69, posite direction to compress and cock the spring and means 251/31; 60/6 including a latching member for holding the valve operating [51] Int. Cl ..Fl6k 31/44, member against movement by the cocked spring and a sole- Fl6k 31/363 noid for moving the latching member to an inoperative posi- [50] Field of Search 251/31, 69, tion thus to release the valve operating member to the action 71, 76; 60/6 ofsaid spring.

PATENTEDJAN 51971 3,552,713

SHEET 1 0F 3 is, [R0872 far 'Gunzizer [LET lfleebery By his Azzamey Ebww/ 9. W4

PATENTEU JAN 51% SHEET 2 BF 3 PATENTEUJAN SIS?! 30552-9713 SHEET 3 BF 3 VALVE OPERATING MECHANISM BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to valve operating mechanisms and involves a further development of the novel valve operating mechanism disclosed and claimed in U.S. application Ser. No. 570,874 filed Aug. 8, 1966, now Pat. No. 3,466,005 by the present applicant for Improvements in Valve Operating Mechanisms.

2. Description of the Prior Art As is indicated in the previous application, the use of remotely located rotary valves for controlling the flow of liquids, gases, etc. to various parts of an industrial plant is a common and wide spread practice and it has been proposed to provide operating mechanisms for such valves by means of which the valves may be operated from a centrally located control station. Commonly, these valve operating mechanism are biased toward one position, usually the closed position, and are releasably held against the action of the biasing means, in the other, usually the open, position. Hitherto, valve operating mechanisms of this'type have been rather complicated in construction as well as quite expensive, especially those made for use with the larger valve sizes. Also, such mechanisms are quite frequently fabricated on the spot with readily available components which are often ill suited for use in the combination. Such arrangements are usually quite complicated and not likely to provide the dependable operation required for safe service.

SUMMARY OF THE INVENTION It is a principle object of this invention to provide a novel and improved mechanism for operating a rotary valve having a stem and an associated valve member which is of relatively uncomplicated mechanical design and yet at the same time is most satisfactory and dependable in operation and especially well adapted for use with the larger sizes of valves. With this object in view and, in accordance with features of this invention, the herein illustrated valve operating mechanism has a base member adapted to be mounted adjacent to the valve to be operated and on which a valve operating member, directly connected to the valve stem, is rotatably mounted. Means are provided herein illustrated as a helical coil spring, tending to rotate the valve operating member and the valve stem in a direction to move the valve member to one of its two positions, together with means for releasably holding the valve operating member against movement in that direction and power operated means for rotating the valve operating member in the opposite direction to compress and cock the spring and move the valve member to the other one of its two positions.

The means for releasably holding the valve operating member against rotation by the spring includes a latch lever carried by the valve operating member, a gate member mounted on the base member for movement to operative and inoperative positions, means for moving the gate member from operative to inoperative position and a latch, or blocking, arm adapted, in its operative position to engage the gate member and hold it in its operative position for engagement by the latch lever on the valve operating member, generally in the same manner as in the mechanism of the above mentioned application.

Preferably, and in accordance with another feature of the present invention, a spring is provided for urging the latch, or blocking. arm to, and for holding it in, operative position and in engagement with the gate member together with a solenoid so arranged that, when the coil of the solenoid is energized, the movement of its armature causes the latch, or blocking, arm to be moved away from its operative position thus freeing the gate member for movement to its inoperative position and releasing the valve operating member for rotation by its associated spring to move the valve member to the first one of its two positions.

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Finally, in accordance with still further features of the in.- vention, the power operated means for rotating the. valve operating member comprises a'piston connected directly to the valve operating member together with means for applying fluid under pressure to the piston for rotating the valve operating member in said opposite direction to compress and cock the spring connected thereto'and t' e the valve member to the other one of its two position d means are provided for simultaneously releasing the v peratihg member to the action of the just mentioned sprm forrelievi'ng' the pressure of fluid against said piston to cau to be moved by the valve operating me g V I tioned one of its two positions. More part cul ar' ly, thej means for applying fluid under pressure includes a pump, an electric motor for driving the pump, a conduit leading from the pump to the piston, a normally open bypass valve in said conduit, a solenoid for closing the bypass valve and means for simultaneously supplying electrical energy to said motor and said solenoid.

The above and other objects and features of thein vention will appear in the following detailed description of ,tlie embodiment illustrated in the accompanying drawings land will be pointed out in the claims. i

BRIEF DESCRIPTION OF THE-DRAWINGS FIG. 1 is a plan view of a valve operating mechanism embodying the features of this invention, with certain parts broken away to expose other parts hidden thereby;

FIG. 2 is a view in side elevation of the mechanism shown in FIG. 1; I 1

FIG. 3 is a view in end elevation of the valve operating mechanism as seen from the left hand end of FIG. 2; 5

FIG. 4 is a plan view of certain of the operating elements of the mechanism shown in different positions assumed-during the operation of the mechanism;

FIG. 5 is a schematic drawing vof the fluid mechanism for moving the valve'in one direction; and

FIG. 6 is an electrical diagram.

Referring to these drawings, especially FIGS. 1, 2 and 3 thereof, the reference character IO'indicates generally a rotary valve having a casing 12 in which there is contained a rotary valve member 14 provided with an operating stem 16. For the purposes of illustration, it will be assumed that this valve is of the same general type as that disclosed in the patent to Laviguer No. 3,164,362, issued Jan. '5, 1965 wherein the flow of fluid through the valve is controlled by rotation of the valve member through an angle of to one or the other of two different positions. For thus rotating the valve member, the novel and improved mechanism now to'be described is provided.

Secured to the valve casing by means of screws 20, 20, FIG. 2, is an adapter plate 22 on which there is, in turn, mounted, by means of screws 24, 24, a second plate or base member 26. This base member is generally rectangular in shape, seeFlG. 1, and on it the valve operating mechanism is supported. The valve stem 16 extends upwardly through aligned apertures formed in the plates 22 and 26 and keyed to the stem isthe hub portion 30 of a disclike valve operating member 32, shaped as more clearly shown in FIG. 4. This valve operating member is rotatably mounted on the base member 26 by means of a combined radial and thrust bearing indicated generally by the reference character 33. Secured to the valve operating member 32, by means of a flange 34 and screws 36', is a shaft 38 which is journaled at its upper end, in a bearing 40 carried by a strut 42, to be referred to below. Rotation of the valve operating member in one direction, to move the valve member to one of itstwo positions, is effected by means of a helical coil spring 44, while for rotating the valve operating member in the opposite direction, thus *to' move the valve member to the other one of its two positions and to compress and cock the spring 44, there is directly con nected to the valve operating member, by means of a clevis50 and pin 52, the rod 54 of a piston 56. This piston is slidable within a cylinder 58having a closed end 60 through which the rod 54 extends. Secured to the other end of this cylinder, by means of screws 64, is a cylindrical extension 66 carrying a plate 68 in which there are mounted upper and lower trunnion shafts 70, 72, FIG. 2. The lower trunnion shaft is rotatably mounted in a bearing bore in the base member 26 while the upper trunnion shaft is rotatably mounted in a crosspiece 78 mounted on the upper ends of two brackets 80, 82, supported and secured to the base member 26. Thus, the cylinder 58 is capable of swinging movement to accommodate the arcuate movement of the pin 52 which occurs as the valve operating member is rotated to move the valve member 14. The spring 44, which is omitted from FIG. 2, surrounds the cylinder 58 and is interposed between the plate 68 and a thrust member 84, mounted on the piston rod 54 and bearing against the clevis 50. The strut 42, referred to above, is secured to the crosspiece 78, directly above the bracket 80, by means of screws 86.

Connected to the closed end of the cylinder 58 is a pipe 90 which, in turn, is connected to apassageway 92, formed in a manifold block 93, by means of a flexible hose 94, the hose and pipe being joined by a union, not shown. Also connected to this passageway, is a conduit 96 and a bypass valve 98, diagrammatically illustrated in FIG. of the drawings. Supported on the base member 26 is a combined pump-motor-sump unit of conventional construction and of a type readily available in the open market. This unit, which is indicated generally by the reference character 100, includes an electric motor 102 coupled to a pump 104. The pump is contained within and adapted to draw pressure fluid from a sump 106 and to deliver the fluid under pressure, limited by the setting of a relief valve indicated generally by the reference character 107, to the conduit 96. As is shown in FIG. 5 a return conduit 108 leads from the bypass valve 98 back to thesump 106.

Associated with the bypass valve 98 is a spring 110, which urges the valve to the position shown in FIG. 5 wherein the conduits 94 and 96 are connected to the return conduit 108, and a solenoid 112 having-a coil 114. When this coil is energized, the valve 98 will be shifted to its other position in which communication between the conduits 96 and 108 is shut off while the conduit 96 is connected to the flexible hose 94 and pipe 90. As will presently appear, electrical energy is supplied simultaneously to the coil 114 and to the motor 102. When this occurs, fluid under pressure will be applied to the piston 56 to cause it to move to the right, .thereby compressing the spring 44 and rotating the valve operating member 32 to the position in which it is shown in FIGS. 1 and 2 of the drawings.

The mechanism for holding the valve operating member in this position, with the spring 44 compressed and cocked, is generally the same as that disclosed in the above identified application and includes a latch lever 130, a gate member 132 and a latch, or blocking, arm 134. The latch lever is pivotally mounted on the lower side of the valve operating member 32 and is yieldingly held in the position in which it is shown, as determined by a stop block 140,- by means of a spring 142. A roll 144, carried by the latch levenengages an abutment surface 146, formed on the operative end of the gate member, when the gate member is held i in its operative position by the latch, or blocking, arm 134, therebyholding the valve operating member 32 against rotation by the spring 44.

The gate member is pivotally mounted, by means of a pin 148, in a block 150 carried by a plate 152. This plate is mounted on the base member 26 for arcuate adjustment about the axis of the valve operating member by means of clamp screws, not shown, which extend through a number of arcuatc slots 154 in the plate. Secured to the plate 152 are two pillow blocks 156, 158 in which a rocker shaft 160 is journaled. Fonned integrally with this shaft and connected by a strengthening web 162 is the latch, or blocking arm 134 and an actuating arm 164, FIG. .1. At its outer end, the arm 134 carries a roll 166 and is formed with a lip providing an abutment surface 168. A coil spring 170, interposed between the plate 152 and the arm 134 constantly urges the arms 134 and 164 toward the positions in which they are shown in FIG. 3. as determined by the engagement of the abutment surface I68 with the lower side of the gate member and with the roll 166 engaging an abutment surface 172 on the gate member. Because of the angularity of the abutment surface 146 on the gate member, when the partsare in the positions shown in' FIG. 1, the spring 44, acting through the roll 144, exerts a force tending to swing the gate member away from the operative position in which it is shown in FIG. 1. Such movement of the gate member is, however, prevented by the latch, or blocking arm 134 when it is heldin its operative position by the spring 170. I

Extending upwardly from the plate 152 are a number of posts 190, 190 and supported on these posts is a platform 192,

FIG. 3. Carried by this platform is a'solenoid 194 having a coil 7 196, FIG. 6, and an armature 198, Secured to and extending downwardly from the armature is a headed plunger 200. A leaf spring 202 yieldingly holds the armature and plunger in the elevated positions in which these parts are shown in FIG. 3, when the coil of the solenoid is deenergized. Upon energization of the coil 196, the armature 198 will be pulled downwardly and the head on the plunger 200 will strike an abutment surface 204 on the arm 164 thereby swinging it and the latch, or blocking arm 134, downwardly and releasing the gate member. The pressure now exerted by the roll 144 on the angularly disposed surface 146 swings the gate member away from the operative position in which it is shown in FIG. 1 to the inoperative position shown in FIG. 4, thus releasing the valve operating member 32 for rotation by the spring 44 in a clockwise direction, as indicated by the arrow in FIG. 4.

In its inoperative position, the gate member engages a stop surface 210, formed on the pillow block 158 and rides over the roll 166. Its operative end passes underneath a bar 212, FIG. 1, which supports this end of the gate member against the upward thrust of the spring 170. At'its opposite end, the gate member is formed with a cam surface 220 and a dwell surface 222, the functions of which will presently appear. Rotation of the valve operating member 32 by the spring is limited to by the engagement of a stop face 230 on the valve operating member with an abutment surface 232 on a stop member 234, adjustably secured to the base member 26 by means of clamp screws, not shown, which pass through elongated slots 236, 236. I

FIG. 1, and omitted from FIG. 4, are three microswitches 240, 242, and 244 provided, respectively, with operating rolls 246, 248, and 250. The switch 244 is spring urged to normally closed position, while switches 240 and 242 are spring urged to normally open positions. As is diagrammatically illustrated in FIG. 6, switch 244 is interposed in a circuit which includes the motor 102 and the coil 1140f the bypass valve solenoid 112; switch 242 is in a circuit including a signal light 252 while switch 240 is in a circuit including a signal light 254. Also included in the circuit with switch 244 is a starting switch 260 and a holding circuit comprising a relay 262 and its associated switch 264. The coil 196 of the solenoid 194 is in a separate circuit which includes a normally open switch 266.

For purposes of illustration, the valve member 14 will be assumed to be in open position, thus to permit the flow of fluid through the valve, when the valve operating member 32 is releasably held in the position in which it is shown in FIGS. 1 and 2 by the engagement of the roll 144 on the latch lever with the abutment surface 146 on the gate member 132 which, in turn, is releasably held in its operative position by the engagement of the roll 166 on the latch, or blocking arm 134 with the abutment surface 172 on the gate member. In order to effect movement of the valve member to its other, e.g., closed position, switch 266 is momentarily closed to energize the coil 196 of the solenoid 194. The gate member is immediately released as a result of the downward movement of the arms 164 and 134 and is moved to its inoperative position,

FIG. 4, by the action of the roll 144 on the angularly disposed abutment surface 146 under the influence of the spring 44.

Supported on the platform '192, which is broken away in The valve operating member is now rotated in a clockwise direction by that spring through an angle of 90 and is brought to a stop by the engagement of the stop face 230 thereon with the abutment surface 232 on the stop member 234, thus moving the valve member to closed position. The spring 44 is partially compressed, i.e., preloaded, when the valve is in this position, thus to insure a full 90 movement of the valve operating member 32 by the spring, and is substantially fully compressed when cocked by the action of the piston 56. During the latter portion of the clockwise rotation of the valve operating member, FIG. 4, a cam roll 270 thereon engages the cam surface 220 on the gate member and swings the gate member in a counterclockwise direction back to its operative position. The roll 270 finally rides onto a dwell surface 222 which is. concentric with the axis of the valve operating member. As the gate member reaches this position, the spring 170 swings the latch, or blocking arm 134 upwardly into its operative position, as shown in FIG. 3. FIGS. 5 and 6 schematically and diagrammatically illustrate the conditions of the fluid pressure operating system and the electrical circuits when the valve operated member is in this position to which it has been moved by the spring 44, e.g., with the valve member closed.

Referring particularly to FIGS. 5 and 6, although switch 244 is in its normally closed position, switches 260 and 264 are open so that the coil 114 of the solenoid 112 is deenergized and no current is supplied to the motor 102. Switch 242 will now be closed by the engagement of a switch actuating plate 280, mounted on the valve operating member 32, with its operating roll 248 thus turning the signal light 252 on. Switch 240 remains in its normally open position with its associated signal light 254 out.

To cause the valve operating member to'be rotated in a counterclockwise direction by the piston 56 which is directly connected thereto, the switch 260 is momentarily closed thus energizing the relay coil 262 and closing the holding circuit switch 264. The coil 114 of the solenoid 112 is now energized, thus moving the bypass valve 98 to a position to shut off the return line 108 and to connect the conduit 96 to the flexible hose 94 and electrical .energy is supplied to the motor 102. Accordingly, fluid under pressure is applied against the piston 56 causing it to move to the right, FIG. 2, thereby rotating the valve operating member in a counterclockwise direction back to the position in which it is shown in FIGS. 1 and 2.

As the valve operating member starts to rotate, switch 242 will open and signal light 252 will go out. When the valve operating member reaches the position shown in FIGS. 1 and 2, switch 240 will be closed by the engagement with its operating roll 246 of a second switch actuating plate 282 mounted on the valve operating member, thereby turning its associated signal light on. Also, the latch lever 130 will be swung by spring 142 to bring its roll 144 into engagement with the abutment surface 146 on the gate member 132. As the latch lever moves to that position, its end will engage the operating roll 250 of the switch 244 and move it to open position, thus deenergizing the coil 114 of solenoid 112 and cutting off the flow of electrical energy to the motor 102. Spring 110 now returns the bypass valve 98 to the position in which it is shown in FIG. 5, thereby connecting the flexible hose with the return line 108. Accordingly, when the valve operating member is next released, in the manner explained above, the operating fluid in the cylinder 58, pipe 90 and flexible hose 94 will flow freely through the return line 108 back to the sump 106, as the valve operating member is rotated in a clockwise direction by the spring 44. If desired, suitable flow control valves may be installed in the conduit 96 and/or the return line 106 for regulating the speed of the rotational movements of the valve operating member in either one, or both, directions.

Like the mechanism disclosed in the above mentioned application, the valve operating mechanism which has just been described while relatively uncomplicated in design is quite efficient and dependable in operation as well as versatile in application and especially well adapted for use with larger size valves. Thus, should it be desired to have the valve member 14 of the valve to be operated latched in a closed position, instead of in the open position as disclosed and described above, the entire valve operating mechanism assembly, including the base member 26, may be mounted on the valve casing 12 in a position from that in which it is shown or the valve stem 16 and the hub portion 30 of the valve operating member 32 can be keyed together 90 from the positions now shown. The various control switches, signal lights, etc. of the electrical system, illustrated in FIG. 6, will usually be located remotely from the valve operating mechanism and the valve to be operated. Also, the switches 260 and 266, herein illustrated as being manually operated, may, of course, be integrated into a more sophisticated logic system.

[claim 1. Mechanism for operating a rotary valve having a valve member rotatable to two different positions for controlling the flow of fluid through the valve and an operating stem, comprising a base member adapted to be mounted adjacent to the valve to be operated, a valve operating member rotatably mounted on the base member, means connecting the valve operating member directly to the valve stem, a spring adapted to rotate the valve operating member in one direction to move the valve member to one of its two positions, means including a latch lever carried by the valve operating member and a cooperating gate member mounted on the base member for releasably holding the valve operating member against rotation by said spring with the valve member in the other one of its two positions, and power operated means connected directly to the valve operating member for rotating said member in the opposite direction to cock the spring and to move the valve member to said other one of its two positions.

2. Mechanism for operating a rotary valve as set forth in claim 1 wherein the gate member is movable to operative and inoperative positions and there are provided means tending to move the gate member to its inoperative position thus to release the valve operating member and means for releasably holding the gate member in its operative position.

3. Mechanism for operating a rotary valve as set forth in claim 2 wherein the means for releasably holding the gate member in its operative position includes a blocking arm adapted in its operative position to engage the gate member to prevent movement thereof to inoperative position and in its inoperative position to release the gate member, and separate means for moving the blocking arm to its operative and inoperative positions.

4. Mechanism for operating a rotary valve as set forth in claim 3 wherein means are provided on the valve operating member for returning the gate member to operative position in response to rotation of the valve operating member by said spring.

5. Mechanism for operating a rotary valve as set forth in claim 3 wherein the means for moving the blocking arm includes a spring for moving the blocking arm to, and for holding it in, its operative position and'a s'olenoid for moving the blocking arm to its inoperative position against the action of said last mentioned spring.

6. Mechanism for operating a rotary valve as set forth in claim 1 wherein said power operated means comprises a piston connected to the valve operating member, means for applying fluid under pressure to the piston for rotating the valve operating member in said opposite direction to move the valve member to the other one of its two positions and means for simultaneously releasing the valve operating member to the action of said spring and relieving the fluid pressure against said piston to cause the valve member to be moved to said first one of its two positions.

7. Mechanism for operating a rotary valve as set forth in claim 6 wherein the means for applying fluid under pressure includes a pump, a conduit leading from. the pump to said piston, a normally open bypass valve in said conduit and means for simultaneously starting said pump and closing the bypass valve.

8. Mechanism for operating a rotary valve as set forth in claim 6 wherein the means for applying fluid under pressure includes a pump, an electric motor for driving the pump, a conduit leading from the pump to said piston, a normally open bypass valve in said conduit, a solenoid for closing said bypass valve and means for simultaneously supplying electrical energy to said motor and said solenoid.

9. Mechanism for operating a rotary valve having a valve member rotatable to two different positions for controlling the flow of fluid through the valve and an operating stem, comprising a base member adapted to be mounted adjacent to the valve to be operated, a valve operating member rotatably mounted on the base member, means connecting the valve operating member directly to the valve stem, a spring adapted to rotate the valve operating member in one direction to move the valve member to one of its two positions, means for releasably holding the valve operating member against rotation by said spring with the valve member in the other one of its two positions, a piston connected to the valve operating member, means for applying fluid under pressure to the piston for rotating the valve operating member in the opposite direction to move the valve member to the other one of its two positions and means for simultaneously releasing the valve operating member to the action of said spring and relieving the fluid pressure against said piston to cause the valve member to be moved by the ,valve operating member to said first one of its two positions.

10. Mechanism for operating a rotary valve as set forth in claim 9 wherein the means for applying fluid under pressure includes a pump, a conduit leading from the pump to the piston, a normally open bypass valve in said conduit and means for simultaneously starting said pump and closing the bypass valve.

11. Mechanism for operating a rotary valve as set forth in claim 9 wherein the means for applying fluid under pressure includes a pump, an electric motor for driving the pump, a conduit leading from the pump to said piston, a normally open bypass valve in said conduit, a solenoid for closing said bypass valve, and means for simultaneously supplying electrical energy to said motor and said solenoid. 

1. Mechanism for operating a rotary valve having a valve member rotatable to two different positions for controlling the flow of fluid through the valve and an operating stem, comprising a base member adapted to be mounted adjacent to the valve to be operated, a valve operating member rotatably mounted on the base member, means connecting the valve operating member directly to the valve stem, a spring adapted to rotate the valve operating member in one direction to move the valve member to one of its two positions, means including a latch lever carried by the valve operating member and a cooperating gate member mounted on the base member for releasably holding the valve operating member against rotation by said spring with the valve member in the other one of its two positions, and power operated means connected directly to the valve operating member for rotating said member in the opposite direction to cock the spring and to move thE valve member to said other one of its two positions.
 2. Mechanism for operating a rotary valve as set forth in claim 1 wherein the gate member is movable to operative and inoperative positions and there are provided means tending to move the gate member to its inoperative position thus to release the valve operating member and means for releasably holding the gate member in its operative position.
 3. Mechanism for operating a rotary valve as set forth in claim 2 wherein the means for releasably holding the gate member in its operative position includes a blocking arm adapted in its operative position to engage the gate member to prevent movement thereof to inoperative position and in its inoperative position to release the gate member, and separate means for moving the blocking arm to its operative and inoperative positions.
 4. Mechanism for operating a rotary valve as set forth in claim 3 wherein means are provided on the valve operating member for returning the gate member to operative position in response to rotation of the valve operating member by said spring.
 5. Mechanism for operating a rotary valve as set forth in claim 3 wherein the means for moving the blocking arm includes a spring for moving the blocking arm to, and for holding it in, its operative position and a solenoid for moving the blocking arm to its inoperative position against the action of said last mentioned spring.
 6. Mechanism for operating a rotary valve as set forth in claim 1 wherein said power operated means comprises a piston connected to the valve operating member, means for applying fluid under pressure to the piston for rotating the valve operating member in said opposite direction to move the valve member to the other one of its two positions and means for simultaneously releasing the valve operating member to the action of said spring and relieving the fluid pressure against said piston to cause the valve member to be moved to said first one of its two positions.
 7. Mechanism for operating a rotary valve as set forth in claim 6 wherein the means for applying fluid under pressure includes a pump, a conduit leading from the pump to said piston, a normally open bypass valve in said conduit and means for simultaneously starting said pump and closing the bypass valve.
 8. Mechanism for operating a rotary valve as set forth in claim 6 wherein the means for applying fluid under pressure includes a pump, an electric motor for driving the pump, a conduit leading from the pump to said piston, a normally open bypass valve in said conduit, a solenoid for closing said bypass valve and means for simultaneously supplying electrical energy to said motor and said solenoid.
 9. Mechanism for operating a rotary valve having a valve member rotatable to two different positions for controlling the flow of fluid through the valve and an operating stem, comprising a base member adapted to be mounted adjacent to the valve to be operated, a valve operating member rotatably mounted on the base member, means connecting the valve operating member directly to the valve stem, a spring adapted to rotate the valve operating member in one direction to move the valve member to one of its two positions, means for releasably holding the valve operating member against rotation by said spring with the valve member in the other one of its two positions, a piston connected to the valve operating member, means for applying fluid under pressure to the piston for rotating the valve operating member in the opposite direction to move the valve member to the other one of its two positions and means for simultaneously releasing the valve operating member to the action of said spring and relieving the fluid pressure against said piston to cause the valve member to be moved by the valve operating member to said first one of its two positions.
 10. Mechanism for operating a rotary valve as set forth in claim 9 wherein the means for applying fluid under pressure includes a pump, a conduit leading from the pump to the piston, a normally open bypass valve in said conduit and means for simultaneously starting said pump and closing the bypass valve.
 11. Mechanism for operating a rotary valve as set forth in claim 9 wherein the means for applying fluid under pressure includes a pump, an electric motor for driving the pump, a conduit leading from the pump to said piston, a normally open bypass valve in said conduit, a solenoid for closing said bypass valve, and means for simultaneously supplying electrical energy to said motor and said solenoid. 